Register of public PNG chunks and keywords, Version 1.3.0 The latest versions of this document, the PNG specification, and related information can always be found at the PNG FTP archive site, ftp://ftp.simplesystens.org/pub/png/. The maintainers of the PNG specification can be contacted by e-mail at png-mng-misc @ lists.sourceforge.net. Abstract This document is the register of public chunks and keywords in the Portable Network Graphics (PNG) specification, version 1.2 [PNG-1.2], and in Portable Network Graphics (PNG) Specification (Second Edition) [PNG-ISO], plus any additional registered "public" PNG chunks and keywords, with their date of registration and location of their specifications. Some chunks listed here are expected to be less widely supported than those defined in the basic specification. However, application authors are encouraged to use these chunk types whenever appropriate for their applications. Additional chunk types and keywords may be proposed for inclusion in these lists by contacting the PNG specification maintainers at png-mng-misc @ lists.sourceforge.net. 1. Register of Public PNG Chunks This table lists the registered public PNG chunks. Chunk Date Formal specification type registered of chunk type IDAT 7 Mar 95 PNG 1.2 IEND 7 Mar 95 PNG 1.2 IHDR 7 Mar 95 PNG 1.2 PLTE 7 Mar 95 PNG 1.2 bKGD 7 Mar 95 PNG 1.2 cHRM 7 Mar 95 PNG 1.2 fRAc 7 Mar 95[1] PNGEXT 1.2.0 gAMA 7 Mar 95 PNG 1.2 gIFg 7 Mar 95 PNGEXT 1.2.0 gIFt 7 Mar 95[2] PNGEXT 1.2.0 gIFx 7 Mar 95 PNGEXT 1.2.0 hIST 7 Mar 95 PNG 1.2 iCCP 17 Aug 98 PNG 1.2 iTXt 9 Feb 99 PNG 1.2 oFFs 7 Mar 95 PNGEXT 1.2.0 pCAL 28 Jan 97 PNGEXT 1.2.0 pHYs 7 Mar 95 PNG 1.2 sBIT 7 Mar 95 PNG 1.2 sCAL 7 Mar 95 PNGEXT 1.2.0 sPLT 9 Dec 96 PNG 1.2 sRGB 6 Nov 96 PNG 1.2 sTER 15 Apr 06 PNGEXT 1.3.0 tEXt 7 Mar 95 PNG 1.2 tRNS 7 Mar 95 PNG 1.2 zTXt 7 Mar 95 PNG 1.2 [1] The fRAc chunk was registered but never formally specified. [2] The gIFT chunk was formally deprecated on 23 Oct 98. 2. Register of Public Text Chunk Keywords This table lists the keywords that have been registered for use in PNG textual chunks. Keyword Date Formal specification registered of keyword Title 7 Mar 95 PNG-1.2 Author 7 Mar 95 PNG-1.2 Description 7 Mar 95 PNG-1.2 Copyright 7 Mar 95 PNG-1.2 Creation Time 7 Mar 95 PNG-1.2 Software 7 Mar 95 PNG-1.2 Disclaimer 7 Mar 95 PNG-1.2 Warning 7 Mar 95 PNG-1.2 Source 7 Mar 95 PNG-1.2 Comment 7 Mar 95 PNG-1.2 All registered textual keywords in iTXt and all other chunk types are limited to the ASCII characters A-Z, a-z, 0-9, space, and the following 20 symbols: ! " % & ’ ( ) * + , - . / : ; < = > ? _ but not the remaining 12 symbols: # $ @ [ \ ] ^ ‘ { | } ~ This restricted set is the ISO-646 "invariant" character set [ISO-646]. These characters have the same numeric codes in all ISO character sets, including all national variants of ASCII. 3. Appendix: Revision History * 30 August 2006 (version 1.3.0): Added sTER chunk. Updated some URLs. * 21 November 2000 (version 1.2.0): First public release, derived from the PNG Specification [PNG-1.2] and the PNG Extensions document [PNGEXT-1.2.0]. 4. References [ISO/IEC-8859-1] International Organization for Standardization and International Electrotechnical Commission, "Information Technology--8-bit Single-Byte Coded Graphic Character Sets--Part 1: Latin Alphabet No. 1", IS 8859-1, 1998. Also see sample files at ftp://ftp.simplesystems.org/pub/png/documents/iso_8859-1.* [ISO-646] International Organization for Standardization and International Electrotechnical Commission, "Information Technology--ISO 7-bit Coded Character Set for Information Exchange", 1991. [PNG-1.2] Randers-Pehrson, G., et. al., "PNG (Portable Network Graphics Format) Version 1.2", which is available at ftp://ftp.simplesystems.org/pub/png/documents/. [PNG-ISO] "Portable Network Graphics (PNG) Specification (Second Edition)," 10 November 2003, also released as "International Standard 15948:2003 -- Portable Network Graphics (PNG): Functional specification", available at http://png- mng.sourceforge.net/pub/png/spec/iso/ [PNGEXT-1.2.0] Randers-Pehrson, G., et. al., "Extensions to the PNG (Portable Network Graphics Format) Version 1.2.0", which is available at ftp://ftp.simplesystems.org/pub/png/documents/. [PNGEXT-1.3.0] Randers-Pehrson, G., et. al., "Extensions to the PNG (Portable Network Graphics Format) Version 1.3.0", which is available at ftp://ftp.simplesystems.org/pub/png/documents/. 5. Credits Editor * Glenn Randers-Pehrson, glennrp @ users.sourceforge.net Document source This document was built from the file pngreg-master-20060914 on 14 September 2006. Copyright Notice Copyright (c) 2000, 2006 by: Glenn Randers-Pehrson This register is being provided by the copyright holder under the following license. By obtaining, using and/or copying this register, you agree that you have read, understood, and will comply with the following terms and conditions: Permission to use, copy, and distribute this register for any purpose and without payment of any fee or royalty is hereby granted, provided that the full text of this NOTICE appears on ALL copies of the register or portions thereof, including modifications, that you make. THIS REGISTER IS PROVIDED "AS IS," AND COPYRIGHT HOLDER MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, COPYRIGHT HOLDERS MAKE NO REPRESENTATIONS OR WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF THE REGISTER WILL NOT INFRINGE ANY THIRD PARTY PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS. COPYRIGHT HOLDER WILL BEAR NO LIABILITY FOR ANY USE OF THIS REGISTER. The name and trademarks of copyright holder may NOT be used in advertising or publicity pertaining to the register without specific, written prior permission. Title to copyright in this register and any associated documentation will at all times remain with copyright holder. End of Register of Public PNG Chunks and Keywords 1.3.0